Solve (4x10^-3)x(9x10^4)

The answer is 1.3x10^2. To solve this you need to multiply the integers first to get 13. The exponents (x10^4 for example) are then multiplied, since it is multiplication the powers are simply added to give x10^1. The 13x10^1 becomes 1.3x10^2 to make it standard form.